An integrated multifractal modelling to urban and regional planning

Abstract

International audienceIn this paper, we propose a conceptual framework for the design of multifractal urban or regional development plans that adhere to five planning principles: hierarchical polycentric urban development; transit-oriented development; locally dense residential development; penetration of green areas into built-up areas across several nested scales; preservation of interconnected networks of natural and green areas having various sizes. This conceptual planning framework is based on multifractal spatial modelling, which is intrinsically multiscalar. The GIS-based software application Fractalopolis (current version 1.0) is used to apply this conceptual framework to real-world case studies. Fractalopolis helps to define where to create new housing units and new facilities in accordance with the planning principles set out above. We use Fractalopolis to create a multifractal development plan for a medium-sized French metropolitan area, namely Besançon, for the year 2026. This plan allows a realistic “soft” transformation the Besançon metropolitan area in keeping with the five planning principles set out above and makes the region more multifractal

An Integrated Modeling Approach Combining Multifractal Urban Planning with a Space Syntax Perspective

“…Weights represent the relative importance of each type of facility for the inhabitants, according to the functional level of the urban center under consideration. Weights have to be chosen to reinforce, to a greater or lesser degree, the functional hierarchy of the spatial system modeled [1]. In our example, the weights for a city have been equally chosen in Equation (7), for example, daily and weekly shopping is equally as important as the opera for the inhabitants of Vienna.…”

“…Aggregation Rules: For synthetic evaluations of suitability for each potential urbanization cell, two sets of aggregation rules have been defined [1,2]. As seen below, the equation for a synthetic accessibility A can be flexibly weighted for any spatial system and temporal scale, for example, daily, weekly, monthly, or rarely.…”

“…It should be noted that a multifractal planning strategy must adhere to the following planning principles [1,2]: hierarchical (polycentric) urban development to manage urban sprawl; transit-oriented development to incorporate sustainable means of transportation; locally well-balanced urban pattern and functions distribution to enhance vital urban systems, local centers, and neighborhoods; penetration of green areas into built-up areas across several nested scales for leisure and microclimate; and the preservation of large interconnected networks of natural and green areas to conserve biodiversity. The multiscale logic of Fractalopolis provides a nested logic allowing for an interlinked accessibility evaluation of the road network, combined with scaling.…”

“…The link between the multifractal logic and the population model is for the reduction factor r 1 a population of ∝ a 1 and for r 2 a population of ∝ a 2 . Consequently, for the first iteration step, the urban population for potential development areas p (1) urb reads:…”

“…For decades now in Western Europe and North America, the phenomenon of urban sprawl has arisen due to a combination of more affordable housing in peri-urban areas and the desirability of residential areas close to green areas, which has also resulted in an increase in trip length to jobs and other facilities [1][2][3][4]. In Latin America, Africa, or Asia, urban sprawl is additionally caused by the pressure of population growth and informal settlements [5,6].…”